In a traditional combustion engine, the linear motion of the pistons is converted into rotational motion using a crankshaft and connecting rod. This approach is inherently inefficient, since the connecting rod and the crank of the crankshaft and the connecting rod and piston in the cylinder run both connect at an angle. As a result, a percentage of power is lost, and designs using a crankshaft have a limited speed of the output shaft of the motor relative to the power of the piston.
Engines have been designed that instead use a rack and pinion system to convert linear motion into rotational motion. U.S. Pat. No. 4,433,649 of Shin shows an internal combustion engine that uses a rack and pinion system to use a long stroke engine with small area pistons. However, the design of Shin still uses a crankshaft, albeit with a reduced function compared to a traditional engine. In Shin, the power output function is removed from the crankshaft; however, a crankshaft is still used to provide a flywheel function and control timing.
U.S. Pat. No. 7,765,803 of Lee et al. also uses a rack and pinion system. As may be seen in FIG. 2 of U.S. Pat. No. 7,765,803, the design uses a multitude of small parts in its construction, which has drawbacks in terms of expense and complication of manufacture and assembly.
U.S. patent application Ser. No. 14/329,338 of Brooks (US Publication No. 2015/0013635) is a rack and pinion system that uses a complex, shaped rack with a steel toe and a milled groove into which is inserted a finger. Moving along the groove, the rack makes a complex movement which results in a loss of power. This design creates a large friction load which is not conductive to work at high engine speeds.